Reci Laser coolant/antifreeze options.

[Raptorex]

Hey folks, just thought I would ask what others are using for a coolant in their laser tubes.
Im in the process of building my own laser cutter using a reci W4 tube, tube just showed up yesterday. And I want to test fire it before I store it away for a few months until I finish building the machine.

Just wondering what folks are using as a coolant additive/antifreeze in their systems. Ive seen a few folks using standard automotive green glycol in their system, but wondering if it will absorb some energy when cooling the optics (im assuming that the coolant flows infront of the beam path in a few places). Im tempted to mix up a batch of Zerex G-05 coolant because its actually almost clear when mixed, and I have a large supply of it (I use it in my cars).

Or I also have another potential source for a (I believe) a clear type glycol designed to be used in liquid cooled tig torches, and im assuming would be designed for applications consisting of a possible high voltage source (ie tig HV arc, dielectric). I personally use plumbing antifreeze in my tig torch, but it is pink, and could have the same optical issues as with green antifreeze. But RV/Plumbing antifreeze is alcohol based, and would naturally be antifungal.


Just would like to hear a few thoughts on the subject. I do want to use something with anti corrosion / anti scaling / anti fungal properties


I never intend to store or use the laser in sub zero temps, but it will be kept in my workshop, and if something does happen (no power / no heat for a few days during winter), I want to make sure I don't have a 1000$ mistake.


I have read thru the forum, and seen a lot of the suggestions, however none seem to be laser specific. I haven't fully unpacked the W4 tube yet, and cant see if the coolant flows thru the front optics.



This machine is going to be a fun build, I honestly cant wait to begin. Its funny how when I started planning all I wanted was a absolute basic bare bones 40w cheapy unit belt drive stepper motor system, and now im in the works for a fully ballscrewed, linear rail servo drive machine. I guess that's how things go sometimes lol

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[Raptorex]

I thought I would give an update to help others with the usefull information I have found on the subject.

First. Although many use plain distilled water in their cutters, even though they don't need any sort of "freeze" protection, plain water without any anti fungal additives could cause bacterial growth on the inside of the tube surface causing a mild reduction in cooling performance.

Now onto coolants. especially for those of us in colder climates.
Many suggest using automotive "green" antifreeze, which is a better alternative, however there is one thing to keep in mind, especially with automotive "green" coolants is the potential issues of the added "sodium silicate" in the coolant to help as a stop leak. Although this could be argued that it could/could not affect a laser cooling system. It is something to keep in mind depending on how your cooling system is designed.

The optimal "anti-freeze" protection coolant would be one based on an ethylene glycol chemistry. There is also a propylene glycol chemistry coolant that is more environmentally friendly, however has a slight reduction in cooling capacity/thermal conductivity compared to a ethylene system. This could be a minor/ insignificant effect on a laser tube cooling system (approx. 1-5% reduction).

If its available, tig welder cooling system coolant is a good alternative, many are clear (after looking at my W4, the coolant loop does not affect optics at all), they are usually ethylene glycol based, and are tested to have a low conductivity with HV.


After looking at some available options to me, I have come to the conclusion I will be going with a Zertex G-05 coolant with a 50/50 mix with distilled water. The MSDS of G-05 lists a 90%+ concentration of Ethlyene Glycol, 3% mix of Diethlyene glycol, 3% mix of Sodium Benzoate (anti fungal additive and corrosion inhibitor), and a 3% mix of Disodium Tetraborate ( acts as a anti fungal and corrosion inhibitor)


I would of like to have used plumbing antifreeze it does contain Propylene Glycol, its main base however is Ethanol, which is flammable. Unless you can guarantee a perfectly lifetime leak free system, there is a mild risk with leaks and the HV. Plus in a closed loop system, it can evaporate and pressurize the coolant loop during temperature rise changes. I have used RV antifreeze in my Tig setup without issues, I will eventually change to G-05 in that system as well.

[Blackened]

Some good info there Raptorex. I'm in a similar position to you. Mid-build of a laser. What sort of chiller are you going to use? I don't have the power supply or resonator yet so I've only done a couple of tests of my chiller using tap water and some old automotive coolant I had laying around the shed. I'll be flushing and using deionised water with some added inhibitors. As yet to be researched for what I can get locally here in Oz.

[cinematic2]

Coolant DOES NOT flow infront of the beam path.

[Dtcrafts]

Coolant DOES NOT flow infront of the beam path.

EXACTLY
even slight condensation on the mirrors will kill the beam
me thinks they are looking to deep into this, just add ant freeze of whatever type